Comparison of advantages and disadvantages of PCB surface coating

A, gold plate (Electrolytic Ni / Au): This coating is the most stable, but the highest price.
b. Immersiog AG is not as good as gold-plated coating and is prone to electromigration resulting in leakage.
c. Electroless nickel plating / gold plate (Electroless Nickel? ImmersionAu, ENIG), when the immersion gold process is unstable, it is easy to produce a black disk.
d. Electroless Tin, lead-free immersion tin is not fully mature.
e. Hot air screed (Sn/Ag/CuHASL), the production process of this coating is not yet fully mature.
f. Organic Solderability Protective Coatings (OSP, OrganicSolderabilityPreservations), which are the cheapest, but the worst performing. When using the OSP board, pay attention to the storage time between the two reflows and between the reflow and wave soldering. Because the protective film on the board pad is damaged after high temperature heating, the solderability is greatly reduced.